A fuel gasification equipment has been developed which uses as fuel solid fuel such as coal, biomass, waste plastic or various wet wastes to produce a gasification gas.
FIGS. 1 and 2 show an example of a conventional fuel gasification equipment comprising a gasification furnace 2 having a fluidized bed 1 of a bed material (such as silica sand or limestone) formed by steam and a fluidizing reaction gas such as air or oxygen to gasify a solid fuel (such as coal or biomass) charged for production of a gasification gas and a flammable solid content, a combustion furnace 5 fed with the flammable solid content produced in the gasification furnace 2 along with the bed material through an introduction pipe 3 and having a fluidized bed 4 formed by a fluidizing reaction gas to burn the flammable solid content, a material separator 8 such as a hot cyclone for separating the bed material from an exhaust gas introduced via an exhaust gas pipe 6 from the combustion furnace 5 to supply the separated bed material to the gasification furnace 2 via a downcomer 7, a material separator 9 such as a hot cyclone for separating a bed material from the gasification gas produced by the gasification furnace 2 and a recovery receptacle 10 for recovering the bed material separated by the separator 9.
In FIGS. 1 and 2, reference numeral 11 denotes a distribution plate for uniformly blowing into the fluidized bed 1 the steam and the fluidizing reaction gas introduced to the bottom of the gasification furnace 2; 12, a partition wall for covering an inner portion of the gasification furnace 2 connected to the introduction pipe 3 such that only a bottom of the portion is opened to prevent the bed material in the fluidized bed 1 from directly flowing out into the introduction pipe 3; 13, a distribution plate for uniformly blowing into the fluidized bed 4 the fluidizing reaction gas introduced to the bottom of the combustion furnace 5; and 14′ denotes a fuel supply pipe connected to a side surface of the gasification furnace 2 at a position higher than an upper surface of the fluidized bed 1.
In the above-mentioned gasification equipment, the fluidized bed 1 is formed in the gasification furnace 2 by the steam and the fluidizing reaction gas such as air or oxygen. A solid fuel such as coal and biomass, which is charged through the fuel supply pipe 14′ into the fluidized bed 1, is partially oxidized for gasification to produce a gasification gas and a flammable solid content. The flammable solid content produced by the gasification furnace 2 is introduced through the introduction pipe 3 along with the bed material into the combustion furnace 5 having the fluidized bed 4 formed by the fluidizing reaction gas to burn the flammable solid content. An exhaust gas from the combustion furnace 5 is introduced through the exhaust gas pipe 6 into the material separator 8 such as a hot cyclone where the bed material is separated from the exhaust gas. The separated bed material is returned through the downcomer 7 to the gasification furnace 2 for circulation.
Since a high temperature is retained in the gasification furnace 2 in the presence of the steam supplied to the bottom of the gasification furnace 2 and moisture evaporated from the solid fuel itself and a gas produced by pyrolysis of the solid fuel and a residual fuel are react with the steam, a water gasification reaction C+H2O═H2+CO and a hydrogen conversion reaction CO+H2O═H2+CO2 occur, producing a combustible gasification gas such as H2 and CO.
From the gasification gas produced by the gasification furnace 2, the bed material is separated by the material separator 9 such as a hot cyclone and is recovered to the recovery receptacle 10.
An equipment configuration similar to the fuel gasification equipment shown in FIGS. 1 and 2 is disclosed, for example, in Patent Literature 1.    Patent Literature 1: JP 2006-207947A